Use the Javax Interceptor API to implement the interceptor function of the Java class library

Use the Javax Interceptor API to implement the interceptor function of the Java class library Overview: The interceptor is a powerful and commonly used programming mode in Java, allowing developers to embed custom logic in the process of method calling, requests and response.The Javax Interceptor API is a set of interceptor interfaces provided by the Java EE specification. By using it, we can easily add a interceptor function to the existing Java library.This article will introduce how to use the Javax Interceptor API to implement the java -class library interceptor function, and provide a complete code example and related configuration description. Step 1: Add the necessary dependencies First, we need to add the following dependencies in the construction of the project (such as Gradle or Maven): <dependency> <groupId>javax.interceptor</groupId> <artifactId>javax.interceptor-api</artifactId> <version>{version}</version> </dependency> Make sure to replace the `{version}` to the required Javax Interceptor API version. Step 2: Define the interceptor class In the Java class library, we need to define a interceptor class to achieve custom logic.The interceptor class must implement the `javax.interceptor.interceptor` interface, and can be marked with the`@interceptor` annotation. The following is the code of a sample interceptor class `loggingInterceptor`: import javax.annotation.Priority; import javax.interceptor.AroundInvoke; import javax.interceptor.Interceptor; import javax.interceptor.InvocationContext; @Interceptor @Priority(Interceptor.Priority.APPLICATION) public class LoggingInterceptor { @AroundInvoke public Object intercept(InvocationContext context) throws Exception { String methodName = context.getMethod().getName(); System.out.println("[INFO] Method invocation intercepted: " + methodName); // Here you can insert custom logic return context.proceed(); } } In the above example, the `loggingInterceptor` realizes the` javax.interCector.interceptor` interface, and use the `@Internetor` annotation to mark it.In addition, we have added `@aroundinvoke` to the` Internet` method, which is used to indicate that the interceptor takes effect during the method call process. Step 3: Configure the interceptor To configure the interceptor for the Java library, we need to add relevant configurations to deployment description files such as `ejb-jar.xml` or` beans.xml`.The following is an example of an example `Beans.xml` configuration: <?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://xmlns.jcp.org/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/beans_1_1.xsd" bean-discovery-mode="all"> <interceptors> <class>com.example.LoggingInterceptor</class> </interceptors> </beans> In the above examples, we add the `loggingInterceptor` class to the` interceptors> `tags.This will tell Javax Interceptor API as a interceptor in the Java class library. Step 4: Use the interceptor Once the interceptor configuration is completed, we can use the interceptor in the Java library.To use the interceptor, just add the `@InternetorBinding` to the target method and specify the interceptor class to apply the interceptor to this method. The following is a code of the Java class that is intercepted by an example: import javax.interceptor.Interceptors; public class ExampleClass { @Interceptors(com.example.LoggingInterceptor.class) public void exampleMethod() { // Execute business logic } } In the above examples, we used the `@Internetors` annotation on the` ExampleMethothod` method, and specified the `loggingInterceptor.class` as the interceptor.This will cause the logic of the interceptor to be triggered every time the `ExampleMethod` method is called. Summarize: Using the Javax Interceptor API can easily add the interceptor to the Java library.We only need to define the interceptor class, configuration interceptor, and use annotations to achieve the function of the interceptor.By interceptor, we can inject custom logic into the method call process to achieve functions such as log records and performance monitoring.I hope this article will help you understand and use the Javax Interceptor API to achieve the interceptor function of the Java library.